<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <input v-model = "val" type="text">
        <button @click = "addItem">添加</button>
        <div>
            <h2>
                正在进行  ---  {{ len }}
            </h2>
            <ul>
                <li v-for="(item, index) in arr" v-show = "!item.checked">
                    <input v-model = "item.checked" type="checkbox">
                    {{ item.val }}     
                    <button @click = "arr.splice(!item.checked,1)">删除</button>
                </li>
            </ul>

            <h2>
                已经完成  ---  {{ arr.length - len }}
            </h2>
            <ul>
                <li v-for="(item, index) in arr" v-show = "item.checked">
                    <input v-model = "item.checked" type="checkbox">
                    {{ item.val }}     
                    <button @click = "arr.splice(item.checked,1)">删除</button>
                </li>
            </ul>
        </div>
    </div>

    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
    <script>
        new Vue({
            el: "#app",
            data: {
                // input中输入的值
                val: "",
                // 总的任务
                arr: []
            },
            computed: {
                len() {
                    return this.arr.filter((item) => {
                        return item.checked === false
                    }).length
                }
            },
            methods: {
                addItem() {
                    this.arr.push({
                        val: this.val,
                        checked: false
                    })
                    this.val = ""
                }
            }
        })
    </script>
</body>
</html>